Contents of this Section:

Global Highlights

The combined global land and ocean surface temperature for September 2010 was 0.50°C (0.90°F) above the 20th century average of 15.0°C (59.0°F) and tied with 1998 as the eighth warmest on record. September 2005 is the warmest September on record.

The September worldwide land surface temperature was 0.66°C (1.19°F) above the 20th century average of 12.0°C (53.6°F)—the ninth warmest September on record.

The September worldwide ocean surface temperature was 0.44°C (0.79°F) above the 20th century average of 16.2°C (61.1°F) and tied with 1998 and 2008 as the ninth warmest September on record.

For January–September 2010, the global combined land and ocean surface temperature was 0.65°C (1.17°F) above the 20th century average of 14.1°C (57.5°F) and tied with 1998 as the warmest January–September period on record.

The global average land surface temperature for the period January–September was the second warmest on record, behind 2007.

The global average ocean surface temperature for the period January–September was also the second warmest on record, behind 1998.

Please Note: The data presented in this report are preliminary. Ranks and anomalies may change as more complete data are received and processed. Effective with the September 2009 State of the Climate Report, NCDC transitioned to the new version (version 3b) of the extended reconstructed sea surface temperature (ERSST) dataset. ERSST.v3b is an improved extended SST reconstruction over version 2. For more information about the differences between ERSST.v3b and ERSST.v2 and to access the most current data, please visit NCDC's Global Surface Temperature Anomalies page.

Introduction

Temperature anomalies for September 2010 are shown on the dot maps below. The dot map on the left provides a spatial representation of anomalies calculated from the Global Historical Climatology Network (GHCN) dataset of land surface stations using a 1961–1990 base period. The dot map on the right is a product of a merged land surface and sea surface temperature (SST) anomaly analysis developed by Smith et al. (2008). For the merged land surface and SST analysis, temperature anomalies with respect to the 1971–2000 average for land and ocean are analyzed separately and then merged to form the global analysis. For more information, please visit NCDC's Global Surface Temperature Anomalies page.

Please Note: This preliminary assessment was made before data from China was made available. Therefore, some of the ranks presented in this report could change when Chinese data is included in the final record.

September

Large portions of the global land surface were much warmer than average during September 2010, contributing to the ninth warmest global land-only temperature on record. The areas with the notable anomalous warmth were western Alaska, most of the contiguous United States, eastern Canada, Greenland, the Middle East, western and far eastern Russia, and northeastern Asia. Cooler-than-average regions included much of Australia, western Canada, parts of the northern United States, central and eastern Europe, and central Russia. The worldwide land surface temperature was 0.66°C (1.19°F) above the 20th century average—this value represented the ninth warmest September on record. The worldwide ocean surface temperature tied with 1998 and 2008 also as the ninth warmest September on record. Warmer-than-average SSTs were present across the Atlantic, western North Pacific, and much of the Indian oceans. The warmth was most pronounced in the northen Atlantic and northwestern Pacific oceans. Cooler-than-average SSTs were present across the eastern and central equatorial Pacific Ocean, and the southern oceans. La Niña conditions strengthened to moderate in September 2010, as SSTs continued to drop across the central and eastern equatorial Pacific Ocean. According to NOAA's Climate Prediction Center (CPC), La Niña conditions are expected to strengthen and last through the Northern Hemisphere spring 2011. Overall, the combined global land and ocean surface temperature for September 2010 was tied with 1998 as the eighth warmest September since records began in 1880. The combined global land and ocean temperature anomaly was 0.50°C (0.90°F) above the 20th century average.

The Northern Hemisphere land surface temperature tied with 2003 as the sixth warmest September on record, while the ocean temperature was the seventh warmest on record. The Northern Hemisphere as a whole—land and ocean combined—was the sixth warmest September on record.

The Southern Hemisphere land surface temperature tied with 2008 as the 12th warmest September on record. The Southern Hemisphere ocean surface temperature also tied with 2008 as the 12th warmest since records began in 1880. The Southern Hemisphere as a whole tied with 2008 as the 11th warmest September on record.

Of interest on a regional level, according to Australia's Bureau of Meteorology (BoM), Australia experienced its coolest maximum temperatures since 1984. Nationally, the daytime maximum temperatures were 1.20°C (2.16°F) below average. In contrast, daily minimum temperatures across Australia for the month were 0.90°C (1.62°F) above average.

Year-to-date (January–September)

The January–September 2010 map of temperature anomalies shows that anomalous warm temperatures were present over much of the world, with the exception of cooler-than-average conditions across the higher-latitude southern oceans, the eastern equatorial and northern Pacific Ocean, the southern tip of South America, and central Russia. The combined global average land and ocean surface temperature for the January–September period tied with 1998 as the warmest such period on record. This value is 0.65°C (1.17°F) above the 20th century average. Separately, the average worldwide land surface temperature ranked as the second warmest January–September on record, behind 2007. The worldwide average ocean surface temperature also ranked as the second warmest such period on record, behind 1998.

The Northern Hemisphere land surface temperature was the second warmest on record for January–September. The ocean temperature was also the second warmest such period on record. The Northern Hemisphere as a whole—land and ocean combined—had its warmest January–September on record.

The Southern Hemisphere land surface temperature was the third warmest September on record, while the ocean surface temperature was the fourth warmest since records began in 1880. The Southern Hemisphere as a whole experienced its second warmest January–September on record.

The average position of the upper-level ridges of high pressure and troughs of low pressure (depicted by positive and negative 500-millibar height anomalies on the September 2010 map, respectively) are generally reflected by areas of positive and negative temperature anomalies at the surface, respectively. For other Global products, please see the Climate Monitoring Global Products page.

Images of sea surface temperature anomalies are available for each week from 2004 to present on the weekly SST page.

Temperature Rankings and Graphics

Global surface temperature stats are not currently available for September 2010.

* Global Ocean tied with 1998 and 2008 as the 9th warmest September on record.* Global Land and Ocean combined with 1998 as the 8th warmest September on record.* Northern Hemisphere Land tied with 2003 as the 6th warmest September on record* Southern Hemisphere Land tied with 2008 as the 12th warmest September on record.* Southern Hemisphere Ocean tied with 2008 as the 12th warmest September on record. * Soouthern Hemisphere Land and Ocean tied with 2008 as the 11th warmest September on record.

Precipitation

The maps below represent anomaly values based on the GHCN dataset of land surface stations using a base period of 1961–1990. Precipitation anomalies on a month-to-month basis are often highly variable across the globe and even within regions.

The areas with the wettest anomalies during September 2010 included Northern Mexico, much of the United States, eastern Canada, Central America, West Africa, much of South, Southeast, and Northeast Asia, most of Australia, and far eastern Russia. The driest anomalies were present across Bangladesh, the Northern Marianna Islands, the Philippines, French Polynesia, the Hawaiian Islands, and the western coast of South America.

Of interest on a regional level, September 2010 was Australia's wettest September of its 111-year period of record, surpassing the record previously set in 1906. Rainfall averaged across the country was nearly two times higher the long-term average, due largely to well-above average rainfall in the tropics and subtropics. Australia's dry season in these regions is typically from May to October, making the heavy rainfall very unusual. The rainfall was associated with the development of moderate to strong La Niña conditions earlier in 2010. By the end of the month, South Australia had already received its average annual rainfall, making 2010 the first above-average year since 2003. While the wet conditions helped alleviate seasonal dry conditions, it was not enough to overcome long-term (14-year) drought deficits in southeastern Australia and southwest Western Australia.

According to Germany's Meteorological Service, Deutscher Wetterdienst, the nationally averaged rainfall for the country was 79 mm (3.11 inches), which is 28 percent greater than the long-term average of 61 mm (2.40 inches). Several locations broke their all-time September monthly rainfall records, including Halle-Köllwitz, in the north central state of Saxony-Anhalt, which received 152 mm (5.98 inches) of rain, breaking its record of 102 mm (4.01 inches) previously set in 1952. Klettwitz, located in the northeastern state of Brandenburg received 160 mm (6.30 inches), which is more than five times higher than its September average of 31 mm (1.22 inches).

Bangladesh experienced its driest monsoon season since 1994. The season, which lasts from June through September, brings the country more than 75 percent of its annual rainfall. While Pakistan and much of India saw above-normal seasonal rainfall, Bangladesh received 1395 mm (54.9 inches) of rain, about 19 percent less than the 30-year long term average of 1720 mm (67.7 inches). During a typical monsoon season, about 25 percent of Bangladesh's land mass is submerged; during the 2010 season, an estimated 16.5 percent was flooded.

Other notable events during September 2010 include the heavy rainfall associated with the remnants of Tropical Storm Nicole that led to floods along the eastern seaboard of the United States. In Wilmington, North Carolina, an estimated 499 mm (19.66 inches) of rain fell between September 27th and September 29th. This was the city's all-time wettest three-day period on record.

Citing This Report

NOAA National Centers for Environmental Information, State of the Climate: Global Analysis for September 2010, published online October 2010, retrieved on August 2, 2015 from http://www.ncdc.noaa.gov/sotc/global/201009.